A virtual colonoscopy is a medical imaging procedure that uses x-ray image data in conjunction with a computer to produce two- and three-dimensional images of a patient's colon (large intestine) from the rectum to the lower end of the small intestine. Images are displayed to help diagnose colon and bowel disease, such as polyps, diverticulosis, and cancer. A virtual colonoscopy can be performed using computed tomography (CT) or with magnetic resonance imaging (MRI), for example.
Colorectal cancer is a leading cause of cancer death in the western world. Virtual colonoscopy is a new method for combined two-dimensional and three-dimensional imaging of the colon, using a multi-slice helical CT scanner, for example. This method has already demonstrated excellent results in polyp and cancer detection, having similar accuracy to Endoscopic colonoscopy in the detection of polyps above 6 millimeters in size. An application of this technique lies in diagnosing cases where conventional colonoscopy fails to demonstrate the entire colon due to technical problems. Another application is to investigate the colon proximal to an obstructing tumor, where both a barium enema and colonoscopy cannot overcome the obstruction. Virtual colonoscopy is also used for population screening.
Virtual colonoscopy has been tied to a radiologist's workstation. Using a thin client application, Web-based access can be possible from a laptop or workstation.